zsmalloc: keep max_object in size_class

Every zspage in a size_class has same number of max objects so we could
move it to a size_class.

Link: http://lkml.kernel.org/r/1464736881-24886-5-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 15 insertions, 17 deletions

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index b6d4f258cb53..79295c73dc9f 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -32,8 +32,6 @@
  *      page->freelist: points to the first free object in zspage.
  *              Free objects are linked together using in-place
  *              metadata.
- *      page->objects: maximum number of objects we can store in this
- *              zspage (class->zspage_order * PAGE_SIZE / class->size)
  *      page->lru: links together first pages of various zspages.
  *              Basically forming list of zspages in a fullness group.
  *      page->mapping: class index and fullness group of the zspage
@@ -213,6 +211,7 @@ struct size_class {
          * of ZS_ALIGN.
          */
         int size;
+        int objs_per_zspage;
         unsigned int index;
 
         struct zs_size_stat stats;
@@ -631,21 +630,22 @@ static inline void zs_pool_stat_destroy(struct zs_pool *pool)
  * the pool (not yet implemented). This function returns fullness
  * status of the given page.
  */
-static enum fullness_group get_fullness_group(struct page *first_page)
+static enum fullness_group get_fullness_group(struct size_class *class,
+                                                struct page *first_page)
 {
-        int inuse, max_objects;
+        int inuse, objs_per_zspage;
         enum fullness_group fg;
 
         VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
 
         inuse = first_page->inuse;
-        max_objects = first_page->objects;
+        objs_per_zspage = class->objs_per_zspage;
 
         if (inuse == 0)
                 fg = ZS_EMPTY;
-        else if (inuse == max_objects)
+        else if (inuse == objs_per_zspage)
                 fg = ZS_FULL;
-        else if (inuse <= 3 * max_objects / fullness_threshold_frac)
+        else if (inuse <= 3 * objs_per_zspage / fullness_threshold_frac)
                 fg = ZS_ALMOST_EMPTY;
         else
                 fg = ZS_ALMOST_FULL;
@@ -732,7 +732,7 @@ static enum fullness_group fix_fullness_group(struct size_class *class,
         enum fullness_group currfg, newfg;
 
         get_zspage_mapping(first_page, &class_idx, &currfg);
-        newfg = get_fullness_group(first_page);
+        newfg = get_fullness_group(class, first_page);
         if (newfg == currfg)
                 goto out;
 
@@ -1012,9 +1012,6 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
         init_zspage(class, first_page);
 
         first_page->freelist = location_to_obj(first_page, 0);
-        /* Maximum number of objects we can store in this zspage */
-        first_page->objects = class->pages_per_zspage * PAGE_SIZE / class->size;
-
         error = 0; /* Success */
 
 cleanup:
@@ -1242,11 +1239,11 @@ static bool can_merge(struct size_class *prev, int size, int pages_per_zspage)
         return true;
 }
 
-static bool zspage_full(struct page *first_page)
+static bool zspage_full(struct size_class *class, struct page *first_page)
 {
         VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
 
-        return first_page->inuse == first_page->objects;
+        return first_page->inuse == class->objs_per_zspage;
 }
 
 unsigned long zs_get_total_pages(struct zs_pool *pool)
@@ -1632,7 +1629,7 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
                 }
 
                 /* Stop if there is no more space */
-                if (zspage_full(d_page)) {
+                if (zspage_full(class, d_page)) {
                         unpin_tag(handle);
                         ret = -ENOMEM;
                         break;
@@ -1691,7 +1688,7 @@ static enum fullness_group putback_zspage(struct zs_pool *pool,
 {
         enum fullness_group fullness;
 
-        fullness = get_fullness_group(first_page);
+        fullness = get_fullness_group(class, first_page);
         insert_zspage(class, fullness, first_page);
         set_zspage_mapping(first_page, class->index, fullness);
 
@@ -1943,8 +1940,9 @@ struct zs_pool *zs_create_pool(const char *name)
                 class->size = size;
                 class->index = i;
                 class->pages_per_zspage = pages_per_zspage;
-                if (pages_per_zspage == 1 &&
-                        get_maxobj_per_zspage(size, pages_per_zspage) == 1)
+                class->objs_per_zspage = class->pages_per_zspage *
+                                                PAGE_SIZE / class->size;
+                if (pages_per_zspage == 1 && class->objs_per_zspage == 1)
                         class->huge = true;
                 spin_lock_init(&class->lock);
                 pool->size_class[i] = class;